/*
 * Copyright (C) 2012 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package interactivespaces.event;

import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Multimaps;
import com.google.common.collect.SetMultimap;

/**
 * A collection of {@link EventListener} instances.
 * 
 * <p>
 * Provides useful methods for wotking with the collection.
 * 
 * @author Keith M. Hughes
 */
public class EventListenerCollection implements EventSubscriber {

	/**
	 * A map of listeners keyed by the event type.
	 */
	private SetMultimap<String, EventListener> listeners;

	public EventListenerCollection() {
		listeners = LinkedHashMultimap.create();
		listeners = Multimaps.synchronizedSetMultimap(listeners);
	}

	@Override
	public void addEventListener(String type, EventListener listener) {
		listeners.put(type, listener);
	}

	@Override
	public void removeEventListener(String type, EventListener listener) {
		listeners.remove(type, listener);
	}

	/**
	 * Send the event to all listeners in the collection for the event type.
	 * 
	 * @param event
	 *            the event to broadcast
	 */
	public void broadcastEvent(Event event) {
		for (EventListener listener : listeners.get(event.getType())) {
			listener.onEvent(event);
		}
	}
}
